The use of conductive compositions to form electrically conductive coatings or paths on substrates is well known. These conductive compositions are applied to various surfaces including circuit boards, glass, ceramics, and the like.
A conductive composition marketed by G-C Electronics of Rockford, Ill., for use on circuit boards consists of 42 wt. % silver, 25 wt. % butyl acetate, and 33 wt. % methyl methacrylate.
U.S. Pat. No. 4,391,742 discloses a paste composition for the production of electrically conductive and solderable structures, wherein the paste comprises 12-40 wt. % organic curable polymer binder, 40-70 wt. % metal salt particles, up to 3 wt. % non-ionic or anionic active wetting agent, and up to 20 wt. % reducing agent. The paste is applied to a nonconductive substrate such as a hard paper substrate by screen printing and cured at a temperature of about 175.degree.-230.degree. C. The polymer binding agent is thermoplastic at the curing temperature, and while the binder is in a softened state at the elevated temperature and before cross-linking is effected, the metal salt particles are carried to the surface of the polymer and become concentrated. After curing of the binder is completed, the composition is exposed to a metallizing bath. The metal salt particles located at or near the surface of the binder are dissolved in the metallizing bath, and metal is deposited in the binder pores formed by the dissolved salts. The thus-obtained metal coating is purported not to serve primarily to produce the electrical conductivity of the conductive path but rather to obtain solderability of the electrical structure. The actual electrical conductivity of the conductive path is said to be determined by the metal particles dispersed in the binder.
U.S. Pat. No. 4,446,059 discloses a conductor composition and conductive element utilizing the composition. The composition comprises 60-98.5 wt. % conductive metal, 1-20 wt. % inorganic binder, 0.5-20 wt. % colorant which is a mixture of an oxide of or a precursor of an oxide of copper, silver, or mixtures thereof and B.sub.2 O.sub.3 or a precursor thereof. The conductor composition is printed onto a substrate by dispersing the composition in an organic medium and using conventional screen printing techniques. The substrate is generally soda-lime window glass, although any glass or ceramic can purportedly be used. The printed pattern is dried at 150.degree. C. for 15 minutes, and the printed substrate is then fired in a box furnace at 600.degree.-700.degree. C. for 7 minutes to effect volatilization of the organic medium and sintering of the inorganic binder, conductive phase, and colorant.